Discs lie in between the body and the ball. Seats provide a seal between the two and support the ball.
For ball valves, suitable ball valve seat materials can be selected according to different working environments.
(1) Peek Ball Valve Seat
It is a high temperature resistant thermoplastic and can be used for a long time at 250°C. Compared with other high temperature resistant plastics such as ZJCLV, etc., the upper limit of the operating temperature is nearly 50°C higher, and PEEK resin is not heat resistant. Compared with other high temperature resistant plastics, the cloth mesh has high strength, high modulus, high fracture toughness and excellent dimensional stability.
(2) PTFE Ball Valve Seat
a. PTFE is an engineering plastic with excellent comprehensive properties, known as the king of plastics.
With excellent chemical stability, even at high temperature and concentrated acid, concentrated alkali or strong oxidant, it does not work. And boiled in concentrated sulfuric acid, concentrated nitric acid, hydrochloric acid or even in aqua regia, it’s weight and performance also are unchanged.
b. It has high heat resistance and cold resistance.
c. It has a very low coefficient of friction and is a good self-lubricating material.
d. It has excellent water resistance, does not absorb water at all, and has good weather resistance and anti-aging properties.
The ball is designed with a center bore (hole)where the media flows through. The direction of the ball is controlled by turning the stem.They are usually made of stainless steel, PVC, chrome plated steel or chrome plated brass. The ball design is categorized as floating or trunnion based on their design and support.
The bore size of these valves is smaller than the diameter of the inlet/outlet connections. Thus, there is a friction loss in the system. However, the losses are still small in comparison to other valves. Most ball valves use a reduced bore design.
(2) Full Bore
A full bore design is also called a full port design. The bore size of these valves is the same size as the diameter of the pipe. Thus, there is no extra friction loss and they are also easy to clean. However, due to its larger diameter, the cost is slightly higher and not required for most application, for which standard reduced bore is sufficient.
(3) V-shaped Bore
The bore in these valves have a V-shaped profile. Thus, a precise flow rate can be achieved by rotating the ball. A linear flow can be achieved by optimizing the profile of the V-shaped bore.
Although most small ball valves can use handwheels, large ball valves or some other dangerous working environments are not suitable for this method. So there are also other ball valve actuators.
(1) Manual Control
These are designed with handles or levers that must be controlled by an operator. This option is not intended for high-cycle applications.